Web services are, in general terms, computer software (or, for ease of reference, software) based services that are provided over a network (e.g., the Internet). More specifically, Web services are self-contained, modularized, executable entities that can be published, searched for, and accessed across a network. Web services are portable across disparate computing platforms because they are implemented according to widely accepted standards.
FIG. 1 is a block diagram of the basic architecture of a conventional Web services framework 100. Conventional Web services framework 100 includes service provider 110, service consumer 120, and service directory 130. Service provider 110 may be, for example, a Web application server that is implemented according to any of the Java 2 Enterprise Edition specifications, for example, v1.3, published on Jul. 27, 2001 (hereinafter, the J2EE standard). One or more Web services are deployed on service provider 110. These Web services comply, at least in part, with the basic Web services standards including: the Extensible Markup Language (XML) standard promulgated by the World Wide Web Consortium (W3C) entitled, “Extensible Markup Language (XML) 1.0 (Second Edition),” 6 Oct. 2000 (hereinafter, the XML standard) and the Simple Object Access Protocol (SOAP) promulgated by the W3C entitled, “SOAP Version 1.1 Part 1: Messaging Framework and Part 2: Adjuncts,” 24 Jun. 2003 (hereinafter, the SOAP protocol).
Service provider 110 publishes one or more Web services on service directory 130 via Web Service Definition Language (WSDL) document 140. A WSDL document may be a document that complies, at least in part, with any of the WSDL standards, for example, the WSDL standard promulgated by W3C entitled, “Web Services Description Language 1.1,” 15 Mar. 2001 (hereinafter, the WSDL standard). WSDL document 140 is an XML document that provides pertinent information about a Web service such as its name, the methods that can be called, the parameters for the methods, and a location for sending requests.
Service directory 130 is a registry and discovery service for Web services. Service directory 130 may implement one of the Universal, Discovery, Description, and Integration of Web services (UDDI) specifications, for example, UDDI Version 3.0, Published Specification, Dated 19 Jul. 2002 (hereinafter, the UDDI specification). The UDDI specification defines a set of SOAP messages that are used to access XML-based data (e.g., WSDL document 140) in a directory. The UDDI specification also defines a registry information model to structure the data stored in service directory 130 and to make it easier to search and navigate.
Service consumer 120 is a computing device that locates and uses a Web service published in service directory 130. Service consumer 120 may be, for example, a Web application server, a general-purpose computer, personal digital assistant, telephone, and the like. Service consumer 120 may implement the UDDI specification to find and retrieve WSDL document 140. A number of files and classes may be generated based on retrieved WSDL document 140 to create a deployable Web service client package on service consumer 120. Service consumer 120 may generate a Web service client (not shown) based on the deployed Web service client package. The generated Web service client may then access the Web service from service provider 110 via, for example, the Internet.
Providing a Web service typically includes specifying the Web service behavior with respect to security, transactions, sessions, access point (e.g., Universal Resource Locator (URL)), etc. Some elements of the specified behavior are system specific. For example, the URL for an access point is clearly specific to the system providing the access point. On the other hand, some elements of the specified behavior could be defined once and remain valid on all of the systems to which the Web service is deployed. Conventional Web services do not distinguish between system specific and system independent behaviors.